diff --git a/src/search.cpp b/src/search.cpp
index f18f2f2f..e7c4e6ca 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -1199,7 +1199,7 @@ namespace {
 
         StateInfo st;
         pos.do_null_move(st);
-        int R = (depth >= 4 * OnePly ? 4 : 3); // Null move dynamic reduction
+        int R = (depth >= 5 * OnePly ? 4 : 3); // Null move dynamic reduction
 
         Value nullValue = -search(pos, ss, -(beta-1), depth-R*OnePly, ply+1, false, threadID);